Linear polyester fiber shrinkage with hno3 or formic acid in a halogenated hydrocarbon and the products so shrunk

ABSTRACT

PROCESS, AND THE RESULTING PRODUCTS, FOR TREATING MATERIALS COMPOSED OF OR CONTAINING POLYESTER STRUCTURES TO ENHANCE THEIR PHYSICAL AND AESTHETIC PROPERTIES AND IMPROVE THE AFFINITY OF THE POLYESTER STRUCTURES TO DYESTUFFS AND OTHER CHEMICALS, COMPRISING THE STEP OF CONTEMPORANEOUSLY CONTACTING SOLID POLYESTER STRUCTURES WITH A HALOGENATED HYDROCARBON OF THE FORMULA CNHMXP, WHEREIN X=CHLORINE OR FLUORINE, N=1 OR 2, P=1 TO 2N+1, AND M=2N+2-P, AND AN ACID SELECTED FROM THE GROUP CONSISTING OF FORMIC AND NITRIC ACID.

United States Patent LINEAR POLYESTER FIBER SHRINKAGE WITH HNO OR FORMIC ACID IN A HALOGENATED HYDROCARBON AND THE PRODUCTS S0 SHRUNK Wolfgang K. F. Otto, Spartanhurg, S.C., assignor to Deering Milliken Research Corporation, Spartanburg, S.C.

No Drawing. Filed Oct. 23, 1968, Ser. No. 770,112 Int. Cl. D04b 19/00; D06m US. Cl. 28-7216 25 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a process for treating polyestercontaining materials, and more particularly for chemically treating synthetic polyester structures, such as fibers, filaments, fabrics, films, and the like, to improve their physical and aesthetic properties and to facilitate the incorporation of dyestuffs and other chemicals into the structures. The invention also relates to the novel products produced by the above treatment.

High molecular weight synthetic linear polyesters, such as the polymethylene terephthalates, are widely employed as fiber-and film-forming compositions. The polyester material in molten form is extruded or otherwise shaped into the desired solid structures, and these structures generally are subjected to a stretching or drawing operation to at least partially orient the molecules thereof and thereby further strengthen and adapt the structures for use.

Due to the relatively dense internal configuration and particular chemical nature of such polyester structures, difficulties are experienced in dyeing the structures, as well as incorporating various chemicals therein during conventional textile finishing operations. It is well known in the dyeing of textile polyester materials to employ certain chemical agents, commonly referred to as carriers, during a dyeing operation to facilitate the incorporation of the dyestuffs into the polyester structures. These chemicals not only serve generally as a solvent for the dyestuffs but also penetrate the polyester structures and are dissolved or absorbed therein to cause a swelling of the structures generally transversely to their axis of molecular orientation. This swelling phenomenon greatly facilitates the introduction of dyestuffs into the polyester structures and results in a deeper dyed product. Typical of such carriers, or dye assistants, are various benzene ring compounds, such as diphenyl, chlorobenzene, benzyl alcohol, and benzoic and naphthoic acid, salicylic acid, formaldehyde, and various other compounds.

In certain instances, it is desirable to dimensionally shrink polyester structures along their axis of molecular orientation subsequent to their formation. For example, When polyester fibers and filaments are fabricated into woven, knitted, or non-woven textile fabrics, it is desirable to longitudinally shrink these structures to compact dimensionally stabilize and impart satisfactory handle to the fabrics, as well as to impart other aesthetic properties to the fabrics. In the packaging field, it is also often desirable to shrink polyester film structures about articles with which they may be employed as a protective covering. It has recently been proposed to shrink textile materials composed of polyester structures by treatment with certain normally liquid partially halogenated methane compounds. U.S. Pat. 2,981,978 discloses such a process for treating oriented crystalline polymeric polyester struc-' tures, such as fibers, filaments, films, and the like, to shrink the materials and improve the handle of fabrics composed thereof.

It is an object of the present invention to provide improved processes of the type described for treating materials composed of or containing polyester structures to greatly enhance their physical and aesthetic properties, as well as to greatly improve the aflinity of the polyester structures to dyestuffs and other chemicals.

It is another object to provide polyester-containing products having improved physical properties.

The above, as well as other objects of this invention, are accomplished by contemporaneously contacting at least partially oriented, solid polyester structures with a halogenated hydrocarbon of the formula C H X wherein X=chlorine or fluorine, n:l or 2, 11:1 to 2n-l-1, and m=2n+2-p, and an acid selected from the group consisting of formic and nitric acid. This unique combination of chemical compounds is absorbed into the polyester structures to produce a synergistic swelling/shrinking action which is greatly increased in degree over that of known swelling agents.

Contemporaneous contact of the polyester structures by the halogenated hydrocarbon and formic or nitric acid not only swells the polyester structures to facilitate the incorporation therein of dyestuffs and other chemicals at room temperatures and atmospheric pressure, but provides exceptionally high shrinkage of the structures along their axis of preferred orientations. This phenomenon can be readily employed to produce improved handle and compactness in textile polyester-containing fabrics as well as provide novel texturizing effects therein. For example, by intermittently treating the surface area of polyester-containing fabrics with the chemicals of the present invention, a seersucker appearance can be achieved. The physical changes produced in the polyester structures by contact with the composition also can be used to produce a crimped yarn product, such as by a knit-deknit process, as well as to achieved a bulked yarn appearance in polyester/wool blend yarns.

The amount of the chemical treating composition which is applied to the polyester structures may be varied, depending on the particular effect being sought. To obtain the maximum shrinking and swelling effect and maximum depth of dyeing, it is desirable to contact the structures with a sufficient amount of the liquid treating composition so as to permit full penetration of the chemicals into the polyester structures. The exact amount of the treating composition which can be absorbed into the polyester structure will vary, depending to an extent upon the degree of molecular orientation and morphology of the structure being treated.

The relative amounts of the components of the treating composition may be widely varied and still provide excellent results in shrinking and swelling of the polyester structures. I have found that exceptional results in shrinkage and dye receptivity can be obtained in textile fabrics and yarns when the two chemicals are employed in about an equal weight ratio, i.e., 50% halogenated hydrocarbon to 5 0% acid, on the polyester materials.

The polyester-containing materials may be contacted with the chemical treating composition in any suitable manner, such as by immersing, padding, spraying, printing, or otherwise contacting the materials with the composition. The halogenated hydrocarbon and the acid need not be applied to the polyester structures simultaneously from a single treating solution, but can be separately applied thereto to effectively swell the structures so long as the two components are contemporaneously present on the structures. In dyeing textile materials containing polyester structures, the composition may be conveniently added to the dyebath or, if desired, the treating composition may be applied to the materials prior to their contact with the dyestuff.

The following examples illustrate various ways in which the present invention may be practiced to provide desired qualities in the polyester structures, and they are not intended to limit the scope of the invention. Percentages in the following examples are given by weight, unless otherwise indicated.

EXAMPLE 1 The following solutions are prepared:

(a) 3200 g. methylene chloride and 800 g, glacial formic acid (97%+) are combined in a beaker and thoroughly mixed.

(b) 200 g. sodium bicarbonate are dissolved in 3800 g.

water.

(c) 3000 ml. water are brought to boil in a beaker.

(d) 3000 ml. methylene chloride are placed in a beaker.

(e) 3000 ml. glacial formic acid (97%+) are placed in a beaker.

Eight 15 inch square samples are cut from a desized and scoured plain weave fabric composed of 100% polyester (Type 54 Dacron by Du Pont) spun yarn. Ten inch markings are applied to the samples in both warp and fill directions, and the samples are numbered 1-8.

Sample #1 is immersed in Solution (a) for 5 minutes and subsequently air dried. Sample #2 is immersed in Solution (a) for 5 minutes, thereafter immersed in Solution (b) for 5 minutes, and then air dried. Sample #3 is immersed in Solution (a) for 5 minutes, then in solution for minutes, and subsequently air dried. Sample #4 is immersed in Solution (a) for 5 minutes and subsequently in Solutions (c) and (b) for 5 minutes each, and then air dried. Sample #5 is immersed in Solution (c) for 5 minutes and then air dried. Sample #6 is immersed in Solution (d) for 5 minutes and then air dried. Sample #7 is immersed in Solution (e) for 5 minutes and subsequently air dried. Sample #8 is immersed in Solution (e) for 5 minutes, then in Solution (d) for 5 minutes, and air dried.

Measurement of Samples 1-8 after the above-described treatments reveals the following area shrinkages in the samples:

Sample No.: Percent area shrinkage 1 27.8

EXAMPLE 2 A 30 inch square sample is cut from a desized and scoured woven fabric having a warp consisting of 65/35% Dacron/cotton spun yarn and a fill consisting of 100% Dacron Type 26 yarn. The sample, after marking with 10 inch shrinkage marks, is immersed in Solution (a) of Example 1 for approximately 2 minutes, subsequently immersed in boiling water, and rinsed in sodium bicarbonate and cold water. After air drying the sample is remeasured and exhibits a shrinkage of 24% in the warp and 28% in the fill directions. The treated sample exhibits a tighter construction and improved handle and drape.

EXAMPLE 3 Two inch square samples of 55/45% Dacron/wool worsted fabric are prepared. Sample #1 is immersed for 5 minutes in Solution (a) of Example 1, subsequently immersed for 5 minutes in Solution (b), and air dried. Sample #2 is immersed for 5 minutes in Solution (a) of Example 1, subsequently immersed for 5 minutes in Solution (c), and air dried. The area shrinkages of Samples l and 2 are 16.4% and 21.5%, respectively. In addition to tighter construction and improved drape, the samples exhibit a more wool-like hand than untreated samples, and inspection under a microscope show a coring effect in the yarns of the fabrics. This results from a concentration of the shrunken polyester components in the center area of the yarn which causes the wool components in the peripheral areas to be forced outwardly to provide a more wool-like hand and appearance to the fabric.

EXAMPLE 4 A sample of 100% Fortrel polyester (Fiber Industries Inc.) Sand Crepe fabric is treated in the manner described for Sample #4 of Example 1 and exhibits an area shrinkage of 56.5%. The fabric not only shows improved cover, handle and drape, but the crepe characteristic of the fabric is developed to an extent not obtainable in fabrics of the same construction which are processed under conventional procedures.

EXAMPLE 5 A sample from the fabric of Example 1 is treated in selected areas thereof with Solution (a) of Example 1. The sample is subsequently immersed for 5 minutes in boiling water and neutralized in Solution (b) of Example 1. A differential shrinkage is produced due to the increased shrinking of the previously treated areas to create a seersucker appearance in the fabric.

EXAMPLE 6 Two 100% Dacron Type 56 polyester double knit fabric samples are prepared. Sample #1 is treated in the same manner as Sample #2 of Example 1, and Sample #2 is treated as Sample #3 of Example 1. Area shrinkages in Samples #1 and #2 are 18.1% and 23.4%, respectively. The knit fabrics after treating exhibit tighter construction, increased weight per unit area, and upon unraveling, or deknitting, the yarn of the fabric retains a. crimp consistent with its previous knit configuration.

EXAMPLE 7 1000 g. chloroform and 1000 g. concentrated nitric acid are mixed and agitated producing an exothermic reaction in the mixture. The mixture is cooled and a fabric sample of Example 1 is immersed therein for 5 minutes. After treatment in boiling water and neutralization as in Example 1, the area shrinkage of the fabric is 35.5%.

EXAMPLE 8 Mixtures are prepared containing and by weight concentrated formic acid and the remainder to consisting of chloroform. Three fabric samples of Example 1 are immersed one in each of the prepared mixtures for approximately 5 minutes. The three samples are subsequently immersed in boiling water and neutralized with sodium bicarbonate solution. After air drying the following warp shrinkages are observed:

Sample No.: Percent area shrinkage l (40%) 24.2 2 (50%) 24.0 3 (60%) 26.0

EXAMPLE 9 Mixtures are prepared containing 10%, 30%, and 50% by weight glacial formic acid (97% and the remainder 100% with methylene chloride. Three fabric samples of Example 1 are immersed one in each of the prepared mixtures for 5 minutes. The three fabric samples are subsequently treated with boiling water and air dried. The following warp shrinkages are observed.

Sample No.: Percent area shrinkage 1 (10%) 21.7 2 (30%) 23.2 3 (50%) 25.2

Each of the samples exhibits improvement in cover, drape and hand.

EXAMPLE 10 360 g. glacial formic acid (97%+), 90 g. methylene chloride, and 50 g. styrene are mixed. A fabric sample of Example 1 is oven dried at 115 F. for 1 hour, weighed and immersed in the above solution for approximately 10 minutes. The sample after removal is neutralized in a sodium bicarbonate solution and placed in a sealed container. The sample is then subjected to beta irradiation of 8 megarads, subsequently extracted in acetone, and oven dried. A weight pickup of 6.2% is observed in the sample. This compares to a pickup of 0.1% in a control fabric which is treated with a solution containing 10% styrene and 90% carbon tetrachloride.

EXAMPLE 1 1 360 g. glacial formic acid (97% and 80 g. methylene chloride are combined with 4 g. of Eastman Fast Blue GLF dyestutf (Disperse Blue #27) Color Index No. 60767 in aqueous solution and stirred. The same amount of the dyestulf is added to a second aqueous solution containing 400 g. of methylene chloride and also agitated. Fabric samples of the fabric of Example 1 are placed in each of the two solutions for 5 minutes and thereafter neutralized in a 5% sodium bicarbonate solution for 1 minute. The samples are subsequently rinsed with acetone and dried. The fabric sample exposed to the mixture of formic acid, methylene chloride and dyestuff exhibits a much deeper dyeing than the sample exposed to the dyestuff and methylene chloride only. The first-mentioned sample also exhibits greater resistance to the removal of the dyestutf by washing.

EXAMPLE 12 A sample of Mylar polyester film (Du Pont) is placed in a beaker containing 320 g. glacial formic acid (97% and 80 g. methylene chloride. After 5 minutes, the film is removed, immersed in boiling water, and subsequently air dried. An area shrinkage of 8% is observed, as compared to a shrinkage of less than 0.1% in a non-treated control film which is immersed for 5 minutes in boiling water.

The foregoing specification has set forth preferred embodiments of the invention and, although specific terms have been employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being limited only by the extent of the following claims.

That which is claimed is:

1. A method of treating materials containing at least partially oriented linear polyester structures comprising the step of contemporaneously contacting the materials with a halogenated hydrocarbon of the formula C H X wherein X=chlorine or fluorine, n=1 or 2, p=1 to 2n+l and m=2n-|-2-p, and an acid selected from the group consisting of formic and nitric acid.

2. A method as defined in claim 1 wherein the materials are contacted with a liquid mixture of the halogenated hydrocarbon and acid.

3. A method as defined in claim 1 wherein the materials are sequentially contacted with the halogenated hydrocarbon and acid.

4. A method as defined in claim 1 wherein the materials are textile materials.

5. A method as defined in claim 4 wherein the textile materials are in staple fiber form.

6. A method as defined in claim 4 wherein the textile materials are in continuous filament form.

7. A method as defined in claim 4 wherein the textile materials are in fabric form.

8. A method as defined in claim 7 wherein the fabric is composed of linear polyester/cotton or linear polyester/ wool blend yarns.

9. A method as defined in claim 1 including the step of dyeing the materials which are contacted with said halogenated hydrocarbon and acid.

10. A method as defined in claim 9 wherein the linear polyester-containing materials are dyed at room temperature and atmospheric pressure.

11. A method as defined in claim 9 wherein the linear polyester-containing materials are impregnated with the halogenated hydrocarbon and acid and thereafter subjected to dyeing.

12. A method as defined in claim 9 wherein the halogenated hydrocarbon and acid are contacted with the linear polyester-containing materials in a dyebath containing the dyestuif.

13. A method as defined in claim 9 wherein the linear polyester-containing materials comprise textile materials in fabric form.

14. A method of modifying the physical properties of textile materials containing at least partially oriented linear polyester structures comprising the step of contemporaneously contacting the materials with a halogenated hydrocarbon of the formula C H X wherein X=chlorine or fluorine, n=1 or 2, 12:1 to 2n+1, and m=2n+2p, and an acid selected from the group consisting of formic and nitric acid to dimensionally shrink the materials.

15. A method as defined in claim 14 wherein the materials are in fabric form and only selected, spaced portions of the materials are contacted to provide a seersucker appearance therein.

16. A method as defined in claim 14 wherein the materials are spun yarns composed of linear polyester fibers and one or more chemically dissimilar fibers.

17. A method as defined in claim 14 including the further step of immersing the chemically contacted materials in a hot aqueous medium to facilitate the shrinkage thereof.

18. A method for facilitating the incorporation of chemicals into at least partially oriented linear polyestercontaining structures comprising the step of contacting the structures with the chemicals and with a halogenated hydrocarbon of the formula C H X wherein X=chlorine or fluorine, n=1 or 2, 12:1 to 2n+1, and m=2n+2p, and an acid selected from the group consisting of formic and nitric acid.

19. A method of texturizing linear polyester yarns comprising the steps of placing an at least partially oriented polyester yarn strand in a desired structural configuration, and contacting the yarn strand while in said coufiguration with a liquid composition containing a halogenated hydrocarbon compound of the formula C H X wherein X=chlorine or fluorine, n =l or 2, p=1 to 2n+1, and m=2n+2p, and an acid selected from the group consisting of formic and nitric acid to produce a substantially permanent crimp in the yarn conforming to the structural configuration in which it is placed.

20. A method as defined in claim 19 wherein the yarn is placed in the desired structural configuration by knitting the yarn into a fabric, and including the further step of deknitting the composition-contacted fabric to provide a crimped yarn product.

21. A method as defined in claim 19 wherein the yarn strand is placed in the desired structural configuration by plying the yarn with another yarn strand, and thereafter separating the yarn strands to provide a crimped yarn product.

22. A textile fabric having improved aesthetic properties and containing at least partially oriented linear polyester fibers or filaments longitudinally shrunk with a composition consisting of a halogenated hydrocarbon of the formula C H X wherein X=chlorine or fluorine,

11:1 01 2, p:l to 2n+l, and m=2n+2p, and an acid selected from the group consisting of formic and nitric acid.

23. An improved textile material containing at least partially oriented linear polyester fibers or filaments which have been chemically treated with a composition com prising a halogenated hydrocarbon of the formula C H X wherein X:chlorine or fluorine, n=1 or 2, [2:1 to 2n+1, and m :2n+2p, and an acid selected from the group consisting of formic and nitric acid to longitudinally shrink the same.

24. A method as defined in claim 23 wherein the linear polyester-containing materials comprise textile materials in staple fiber form.

25. A method as defined in claim 9 wherein the linear polyester-containing materials comprise textile materials in yarn form.

References Cited UNITED STATES PATENTS 3/1949 Whinfield et a]. 8-130.1 DIG 4 8 2,828,181) 3/1958 Sertorio 8174 X 2,856,638 10/1958 Schulken et al. 8-1301 DIG 4 2,981,978 5/1961 Grifling 8-1301 DIG 4 3,129,053 4/1964 Castle 893 3,446,886 5/1969 Karickhoff 8130.1 X 3,514,249 5/1970 Bullington 8-130.1

FOREIGN PATENTS 524,897 8/1940 Great Britain 813l OTHER REFERENCES Diserens, Chemical Technology of Dyeing and Printing, vol. 2, pp, 275 and 315317, pub. by Reinhold Publishing C0. 1951, TP893D49pE.

DONALD LEVY, Primary Examiner US. Cl. X.R. 

